Nuestros investigadores

Germán Ramos Ruiz

Construcción, Instalaciones y Estructuras
Escuela Técnica Superior de Arquitectura. Universidad de Navarra
Líneas de investigación
Building environmental design

Publicaciones científicas más recientes (desde 2010)

Autores: Ramos, Germán; Elucas; Fernández, Carlos;
ISSN 1996-1073  Vol. 12(1)  Nº 34  2019  págs. 1 - 18
There is growing concern about how to mitigate climate change in which the reduction of CO2 emissions plays an important role. Buildings have gained attention in recent years since they are responsible for around 30% of greenhouse gases. In this context, advance control strategies to optimize HVAC systems are necessary because they can provide significant energy savings whilst maintaining indoor thermal comfort. Simulation-based model predictive control (MPC) procedures allow an increase in building energy performance through the smart control of HVAC systems. The paper presents a methodology that overcomes one of the critical issues in using detailed building energy models in MPC optimizations¿computational time. Through a case study, the methodology explains how to resolve this issue. Three main novel approaches are developed: a reduction in the search space for the genetic algorithm (NSGA-II) thanks to the use of the curve of free oscillation; a reduction in convergence time based on a process of two linked stages; and, finally, a methodology to measure, in a combined way, the temporal convergence of the algorithm and the precision of the obtained solution.
Autores: elucas; HuDu; Ramos, Germán; et al.
ISSN 1996-1073  Vol. 12(7)  Nº 1309  2019  págs. 1 - 16
The use of Building Energy Models (BEM) has become widespread to reduce building energy consumption. Projection of the model in the future to know how different consumption strategies can be evaluated is one of the main applications of BEM. Many energy management optimization strategies can be used and, among others, model predictive control (MPC) has become very popular nowadays. When using models for predicting the future, we have to assume certain errors that come from uncertainty parameters. One of these uncertainties is the weather forecast needed to predict the building behavior in the near future. This paper proposes a methodology for quantifying the impact of the error generated by the weather forecast in the building¿s indoor climate conditions and energy demand. The objective is to estimate the error introduced by the weather forecast in the load forecasting to have more precise predicted data. The methodology employed site-specific, near-future forecast weather data obtained through online open access Application Programming Interfaces (APIs). The weather forecast providers supply forecasts up to 10 days ahead of key weather parameters such as outdoor temperature, relative humidity, wind speed and wind direction. This approach uses calibrated EnergyPlus models to foresee the errors in the indoor thermal behavior and energy demand caused by the increasing day-ahead weather forecasts. A case study investigated the impact of using up to 7-day weather forecasts on...
Autores: Gutiérrez-González, V., (Autor de correspondencia); Álvarez-Colmenares, L.; López-Fidalgo, J.; et al.
ISSN 1996-1073  Vol. 12  Nº 11  2019  págs. 2096
Building Energy Models (BEMs) are a key element of the Energy Performance of Buildings Directive (EPBD), and they are at the basis of Energy Performance Certificates (EPCs). The main goal of BEMs is to provide information for building stakeholders; they can be a powerful market tool to increase demand for energy efficiency solutions in buildings without affecting the comfort of users, as well as providing other benefits. The next generation of BEMs should value buildings in a holistic and cost-effective manner across several complementary dimensions: envelope performances, system performances, and controlling the ability of buildings to offer flexible services to the grid by optimizing energy consumption, distributed generation, and storage. SABINA is a European project that aims to look for flexibility to the grid, targeting the most economic source possible: existing thermal inertia in buildings. In doing so, SABINA works with a new generation of BEMs that tend to mimic the thermal behavior of real buildings and therefore requires an accurate methodology to choose the model that complies with the requirements of the system. This paper details our novel extensive research on which statistical indices should be chosen in order to identify the best model offered by the calibration process developed by Fernandez et al. in a previous paper and therefore is a continuation of that work.
Autores: Fernández, Carlos, (Autor de correspondencia); Muñoz Mardones, Ana Fei; Du, H.; et al.
ISSN 1996-1073  Vol. 11  Nº 11  2018  págs. 3139
This study presents a novel optimization methodology for choosing optimal building retrofitting strategies based on the concept of exergy analysis. The study demonstrates that the building exergy analysis may open new opportunities in the design of an optimal retrofit solution despite being a theoretical approach based on the high performance of a Carnot reverse cycle. This exergy-based solution is different from the one selected through traditional efficient retrofits where minimizing energy consumption is the primary selection criteria. The new solution connects the building with the reference environment, which acts as an unlimited sink or unlimited sources of energy, and it adapts the building to maximize the intake of energy resources from the reference environment. The building hosting the School of Architecture at the University of Navarra has been chosen as the case study building. The unique architectural appearance and bespoke architectural characteristics of the building limit the choices of retrofitting solutions. // therefore, retrofitting solutions on the facade, roof, roof skylight and windows are considered in multi-objective optimization using the jEPlus package. It is remarkable that different retrofitting solutions have been obtained for energy-driven and exergy-driven optimization, respectively. Considering the local contexts and all possible reference environments for the building, three unlimited sinks or unlimited sources of energy are selected for the case study building to explore exergy-driven optimization: the external air, the ground in the surrounding area and the nearby river. The evidence shows that no matter which reference environment is chosen, an identical envelope retrofitting solution has been obtained.
Autores: Fernández, Carlos; Ramos, Germán;
ISSN 1996-1073  Vol. 10  Nº 12  2017  págs. 2102
Building energy performance (BEP) is an ongoing point of re¿ection among researchers and practitioners. The importance of buildings as one of the largest activators in climate change mitigation was illustrated recently at the United Nations Framework Convention on Climate Change 21st Conference of the Parties (COP21). Continuous technological improvements make it necessary to revise the methodology for energy calculations in buildings, as has recently happened with the new international standard ISO 52016-1 on Energy Performance of Buildings. In this area, there is a growing need for advanced tools like building energy models (BEMs). BEMs should play an important role in this process, but until now there has no been international consensus on how these models should reconcile the gap between measurement and simulated data in order to make them more reliable and affordable. Our proposal is a new generation of models that reconcile the traditional data-driven (inverse) modelling and law-driven (forward) modelling in a single type that we have called law-data-driven models. This achievement has greatly simpli¿ed past methodologies, and is a step forward in the search for a standard in the process of calibrating a building energy model.
Autores: Ramos, Germán; Fernández, Carlos;
ISSN 1996-1073  Vol. 10  Nº 10  2017  págs. 1587
Nowadays, there is growing interest in all the smart technologies that provide us with information and knowledge about the human environment. In the energy ¿eld, thanks to the amount of data received from smart meters and devices and the progress made in both energy software and computers, the quality of energy models is gradually improving and, hence, also the suitability of Energy Conservation Measures (ECMs). For this reason, the measurement of the accuracy of building energy models is an important task, because once the model is validated through a calibration procedure, it can be used, for example, to apply and study different strategies to reduce its energy consumption in maintaining human comfort. There are several agencies that have developed guidelines and methodologies to establish a measure of the accuracy of these models, and the most widely recognized are: ASHRAE Guideline 14-2014, the International Performance Measurement and Veri¿cation Protocol (IPMVP) and the Federal Energy Management Program (FEMP). This article intends to shed light on these validation measurements (uncertainty indices) by focusing on the typical mistakes made, as these errors could produce a false belief that the models used are calibrated.
Autores: Ramos, Germán; Fernández, Carlos;
ISSN 0306-2619  Vol. 185  Nº 1  2017  págs. 82 - 94
Nowadays there is a growing concern about climate change and the global warming effect produced by the concentration of greenhouse gases (GHG). At the Paris climate conference (COP21), 195 countries adopted a global climate agreement, limiting global warming to well below 2ºC. Buildings are large producers of GHG and therefore international standards such as ISO 50001 focus on improving their energy performance, including energy ef¿ciency, use and consumption. To achieve this goal it is important to have a detailed knowledge of the thermal behaviour of uildings. The International Performance Measurement and Veri¿cation Protocol (IPMVP), proposes a calibrated simulation model (Option D) to gather this knowledge and to determine the savings associated with Energy Conservation Measures (ECMs). This paper improves the calibration methodology proposed by Ramos et al. (2016) [1], solving the limitations regarding the number of thermal zones and the use of free-¿oating time periods. Through a real case-study that guides the process, the paper explains how to achieve a calibrated Building Energy Simulation (BES) model using an optimisation process based on a meta-heuristic strategy (genetic algorithm - NSGA-II). Different uncertainty indices such as: CV(RMSE) and Goodness of Fit (GOF) are used as objective function to obtain the calibrated model. These indices, frequently used to measure the accuracy of models, are combined to provide a double possibility to ¿nd the best solution,
Autores: Ramos, Germán; Fernández, Carlos; Gómez-Acebo, T; et al.
ISSN 0306-2619  Vol. 168  2016  págs. 691 - 705
Buildings today represent 40% of world primary energy consumption and 24% of greenhouse gas emissions. In our society there is growing interest in knowing precisely when and how energy consumption occurs. This means that consumption measurement and verification plans are well-advanced. International agencies such as Efficiency Valuation Organization (EVO) and International Performance Measurement and Verification Protocol (IPMVP) have developed methodologies to quantify savings. This paper presents a methodology to accurately perform automated envelope calibration under option D (calibrated simulation) of IPMVP ¿ vol. 1. This is frequently ignored because of its complexity, despite being more flexible and accurate in assessing the energy performance of a building. A detailed baseline energy model is used, and by means of a metaheuristic technique achieves a highly reliable and accurate Building Energy Simulation (BES) model suitable for detailed analysis of saving strategies. In order to find this BES model a Genetic Algorithm (NSGA-II) is used, together with a highly efficient engine to stimulate the objective, thus permitting rapid achievement of the goal. The result is a BES model that broadly captures the heat dynamic behaviour of the building. The model amply fulfils the parameters demanded by ASHRAE and EVO under option D.
Autores: Sánchez-Ostiz, Ana; Monge, Aurora; San Miguel, Jorge; et al.
Libro:  Construction, pathology, rehabilitation, technology and heritage, rehabend 2018.
2018  págs. 1807 - 1815
Autores: Sánchez-Ostiz, Ana; Monge, Aurora; Domingo, Silvia; et al.
Libro:  Rehabend 2016. Euro-american congress. Construction, Pathology, Rehabilitation technology and Heritage management
2016  págs. 1632 - 1640
Autores: Sánchez-Ostiz, Ana; González, María Purificación; Echeverria, Juan Bautista; et al.
Libro:  Adaptive Facade Network Europe
Vol. 1  Nº 1  2015  págs. 29
Autores: Pellicer, Domingo; González, María Purificación; Sanz, Cristina María; et al.
Libro:  International congress on education, innovation and learning technologies
2014  págs. 232 - 233
Autores: Ramos, Germán; Fernández, Carlos;
Libro:  Proceedings of World Sustainable Building: WSB 14
Vol. 4  2014  págs. 327 - 334
In the design of new buildings, project energy efficiency is nowadays one of the most important parameters on its development. The energy crisis on which we live and the greater social awareness have allowed efficiency be a major factor when we are thinking in a new building solution. This search for efficiency must be supported by studies to quantify these improvements. With this information we can assess which one of the different solutions is the best. The building sustainability is closely related to building efficiency. The present analysis shows through a semi-attached house, the importance of building orientation in heating and cooling demands. With this knowledge we can choose the orientation with low energy consumption.
Autores: Ramos, Germán; Fernández, Carlos;
Libro:  Jornadas internacionales de investigación en construcción
2013  págs. 126
Autores: Torres Ramo, Joaquín; Ramos, Germán; et al.
Libro:  IV Jornadas Internacionales sobre investigación en arquitectura y urbanismo
2011  págs. 1 - 15
Autores: Quintanilla Crespo, V; Torres Ramo, Joaquín; Ramos, Germán;
Libro:  Puente de Aoiz (Aoiz-Agoitz). Restauración y adecuación de su entorno 2010.
2011  págs. 213 - 254
Autores: Vidaurre-Arbizu, Marina; Ramos, Germán; Torres Ramo, Joaquín; et al.
Libro:  37th IAHS world congress on housing science: Design, technology, refurbishment and management of buildings
2010  págs. 325
"In the Department of Construction Science, we have developed and documented a specific model of systematized process in order to carry out activities of R&D&I oriented to a detailed design of constructive systems of innovative façades. This specific model will be used as a guide for the study, analysis, design and evaluation of the proposed solutions for façades. This model of systematized process of research provides a general idea of the set of stages and activities in the processes of R&D&I, with a graphical map and a documentary structure that describes how all the process works, step by step, facilitating its comprehension and application. The protocol details the key procedures within the global process. This protocol allows elaborating the programme of necessities derived from the conditionings, requirements and demands related to every specific façade, assisting with the definition of the technical characteristics of its parts and components to approach the conceptual and graphical design of constructive solutions, in successive stages. This protocol provides the means to analyze and evaluate every particular design of façade and the process of R&D&I that has been followed, so that it allows to justify and demonstrate the fulfilment of the requirements and demands that concern every stage of the complete life cycle of façades, and to identify fields that could be improved in the R&D&I process, in order to apply corrective actions. This protocol is complemented by som
Autores: Vidaurre-Arbizu, Marina; Ramos, Germán; Torres Ramo, Joaquín; et al.
Libro:  Solar Buildings Skins: conference proceedings of the 5 energy forum
2010  págs. 131 - 135
Autores: Pellicer, Domingo; Sanz, Cristina María; Ramos, Germán;
Autores: Pellicer, Domingo; Ramos, Germán;